Air blast device



Patented Apr. 4, 1950 UNITED STATES PATENT OFFICE 2, 2 94 AIR BLAST DEVICE Frank H; A s r n Chich m, 111,, ass g r to. Armstrong Qoalbreak Company, Benton Harbor, Mich, a corporation of Michigan Application October 24, 194;7 Serial- No.- 181 949; 14 Claims. (Cl. 132 25) Ifhis. invention relates to blasting devices, and

more particularly to. a deviceused in mining materials, such as. coal, for the purpose. of breaking down the coal or other material to be mined from the vein within the mine without requiring the use of explosives or of combustion.

The primary object of the invention is to provide a novel, simple, rugged device of this character which may here-used repeatedly, and which is easy tomanipulate and to adjust.

A further object is to provide a device of this character wherein the number of working parts isreduced to a minimum.

A further object is to provide a device of this character which has means for insuring an instantaneous discharge of the. compressed air blast.

A further objectis to provide a device of this character having a member adapted to be sheared at. a given pressure which forms the. control for the blast discharge, which member is provided with novel means for mounting the. same in selected position.

A further object is to provide a device of this character having a pressure responsive member adapted to be shifted to blast charge releasing position upon the attainment of a predetermined pressure in arapid manner, such member being so. constructed and cooperating with the remaining parts of the device that. its operation is auto? matically cushion d against injurious impact.

A further ob ect is, to provide a device of this character which is so constructed that it. is partly disassembled in a single rapid manipulation after each use order to condition it for reuse and in w i h. he disa sem y a o ds or n y for the user to, inspect the device, to clean it, and to observe any defects, prior to each use.

A further object is to provide a device of this character in which it is impossible for air or gas at high pressure tobe trapped due to breakage of internal parts.

Other objects will be apparent from the followpecific onn. he d win Fig. 1 is a longitudinal sectional View taken on line l.-!. of Fig. 3 and illustrating the parts in the r. h r in position.

Fig. 21s alongitudinal sectional view similar to Fig, 1 but illustrating the parts. in their discharge or blast. releasing position.

Fig 3 is a transverse sectional view of the device taken on line lie-=3. of Fig. 1.

Referring to the drawin thenumeral l designates a tubular body member which is formed of a diameter to. fit. freely and slidably within a bore hole open at the working face of the coal to be broken down by the device and which is elongated in length; for example, the length of the tube ma be. in. the ordo o fio in hes ug h dimension s gi en. a illustrative only a d is. not

m t n T o ub W s io m o a s e h o withstand pressures considerably in. excess ofthe defined blasting pressure. Thus, it the blasting pressure istobe in the order of 10,00,0pounds, per squareinchthe tube will beof astrength to with; nd. r s r o 1 0op 1m p r qu r i c o mo The iopo t nds. tho ub pre -e il have re ed neck portions, I l which are eigt r a y re eaded...

on nd. ca 2. i p v d h an. inte nall screw-threaded shirtv Ii? at, one end thereoi which ha th a ed ommotion w t he; nec U. at one and. o h tubula odx T n cap 2. s. i rably provided. with a centra ocke IA. at ts, outer end which. c ves a lu r fi t n '5 hav n a. ne t hich i scr w-thre ded no oehtra h re in heeh an 12.. The l g, l5.p1:e, er h x ha a. cen al passa e. e tend n there,- through with which av conduit l8 communicates. The outer n o he s, 5. preferably. has a screw-thre d. ontrol. r ss. there figu e t provide a. uppor o a fla d inne end portion oi h ondui it. which. w ged and. clamped n p essu e. seal n rel on. b a. fi n l s e thread d ntho QQket of th fi tin l5 and. resses a a nst. the cond and. The transverse fooeo t o. end a '2. a ace to th end U. o ho. body is. provided with. n annul r gr ov mountin a seal m mber 20.. su as. n O t ns. w ich. i presse a ainst. the end. of the body In incident. o mounting of t ca 2.11pm sai body and; wh ch p ov des. a ntin ous rt h r s ur a be.- 'woen th and ca and the body, It. will be, understood. that. he condui .8. exten s to. sour e o as. uch a r. und rh ghprossure. our ei her he a compres or or a ank of lar e volume, oontain hs r o other as at. pr ss r re tor than he desired blast n pre su o t s (low The. ondui ll he e on ated to eri the, o it on n of th s urce. o oomn es e a r emote from t e w rki g ace o e coal. or her ma eria to b brok n. owa. o pur e i safetr.

The end of the body Ill opposite that which mounts the end cap. [2. m uhts a ri id. cu -shaped h ad. Th e nd the h ad 2. ha a. skir 26 which is n l y. strawhre ded upon the ad ace t. ho k. l o he h tl the thr ad r erably having fast. lead to. pe mit. maid p ioat o the h ad 5. theh dy l0, an r pi romoyal f h a from t rb d L he. head 2.5. r v d with an int or stopped r .1 111.- der d onfi uration adjacen t th skirt. 2.5 th some h les pr ridod for the, urp se, o recei in a be ri g. ring an a shea r n 2B.- Th ri 2. ma b f rm o fi o or thi h d. stoo or of ny th ma e ial an i oha ze b a inne amet whi h is l than. the nner d e o t h ok H i the bod "1- adiaoe t thereto. The ring 28 is preferably fixedly mount 11 h h ad .5. and th hear as 2.3 s oosely removably mounted for ready insertion and replacement. A circumferential groove is formed in the end of the body l facing head 25 and receives an annular sealing member 30, such as an O ring. An effective seal is provided between the parts when the head 25 is threaded upon the tubular body In by the pressure exerted by the head against the rings 28 and 29,.which is in turn transmitted against the O ring 30.

The inner diameter of the portion 3! of the bore of the head leading from the skirt 26 is preferably of a dimension slightly greater than the inner diameter of the neck portion ll adjacent thereto. A plurality of radial discharge outlets 32are formed in the head 25 with their axes preferably inclined to both the axis of the head and the perpendicular to that axis, as illustrated. The openings 32 communicate with the portion 3| of the bore intermediate the length thereof.

At its inner end the portion 33 of the bore is of a reduced or lesser diameter and forms with the end wall 34 a terminal cavity 35. A shoulder 35 is. formed between bore portions 3! and 33, and a scraper or wiper ring 31, whose inner diameter is preferably the same or slightly less than the diameter 33 of the chamber 35, bears against said shoulder. A plurality of retainers 38 are carried by the head and project into the chamber defined by the bore portion 3| for the purpose of retaining the annular gasket. member 3'! in proper position bearing against said shoulder. An annular groove is formed in the interior small diameter bore portion 33 adjacent to the shoulder 36 and is adapted to receive and mount a sealing member 39, such as an O ring. The end wall 34 of the head is provided with a, plug 40 projecting centrally and inwardly thereof for purposes to be described.

A plunger of hollow construction and generally cylindrical shape is mounted in the device. The plunger 45 has an opening 46 positioned centrally at one end thereof, said opening being of a diameter .to have a snug sliding fit around theplug 40 of the head when the parts are positioned as illustrated in Fig. 2. A somewhat larger opening 41 is provided centrally in the opposite end ofthe plunger 45. The outer diameter of the plunger is such that it has a snug sliding fit in the inner small diameter bore portion 33 of the head, and the plunger is preferably tapered at 48 at one end. The opposite end of the plunger is of greater diameter and has a radially outwardly projecting portion which terminates in an annular knife edge 49 adapted, in the position of the parts shown in Fig. l, to bear against the inwardly projecting portion of the shear ring 29. The diameter of the enlarged head portion 50 of the plunger is preferably slightly greater than the inner diameter of the major portion of the .neck I l, and said neckis stepped at its outer end at 5| to provide a stop preventing movement of the .plunger 5|! into the body l0.

It will be observed that the device may be con- .ditioned for charging by applying a shear ring 29 in proper position in the head 25 to bear against the ring 28. The plunger 45 is then inserted into the head with its inner end positioned and centered by the reduced bore portion 33 and its outer enlarged head 50 bearing against the shear ring 29. When so assembled the head is threaded upon the body, the fast lead of the threads 21 facilitating rapid connection of the parts. The head is rotated until a firm frictional abutment is obtained between the ring 29 and th ring 28 on one side thereof and the sealing ring 30 on the other side thereof. Inasmuch as 4 the head 59 of the plunger bears against the shoulder 5|, the tightening of the head 25 upon the body serves to cause the annular knife edge 58 of said head to bite into the shear ring 29. When the parts are so positioned, an effective seal of the outlet 32 is provided at one end of the plunger 45 by the shear ring and its cooperating sealing ring 30 and at the other end of the device by the O ring 39.

The device so conditioned is inserted into the bore hole and suitably tamped in place in the manner well understood in the art. The operator then retires to a safe position, and gas, such as air under high pressure, is introduced into the body it through the conduit 58 and the plug member ll. It will be observed that the interior of the body ,I I] and of the head 25 is substantially unrestricted and, therefore, a maximum volume or storage capacity for compressed air is provided. The effective area of the head 50 at the left end of the plunger 45 is greater than the area of the plunger at the other end, and, consequently, in the presence of a charge of gas at a pressure above atmosphere, the plunger 45 is forced or urged toward the right, as viewed in Fig. 1. This force acts through the knife edge 43 against the shear ring 29. When the pressure of the charge reaches a predetermined point, it produces a difference. between the forces acting at the opposite ends of the plunger of a predetermined value sufficient to cause the knife edge 49 to shear the ring 29. This frees the plunger which may rapidly move to the Fig. 2 position, thereby opening the outlets 32 for the rapid exhaust of the blasting charge to create the desired blast action. As the plunger 45 moves to the right it is guided bythesmall diameter bore portion 33 and moves with the full impact or force produced by the differential pressure action upon its opposite ends until the opening 46 thereof moves around the plug 40. Thereafter continued movement of the plunger serves to compress the gas ahead or to the right of the plunger and to build up a compressed gas ushion I which will reach a value counterbalancing or counteracting the charge pressure within the device before the plunger is permitted to strike the end wall 34. Consequently, the plunger 45 is prevented from striking said end wall and the movement of the plunger is cushioned effectively to prevent impact which would tend to injure either the plunger or the head 25.

The ring 31 which encircles the plunger 45 servesas a wiping member. Consequently, any

. dust, dirt or abrasive particles upon the outer periphery of the plunger are wiped therefrom incident to the releasing action of the plunger in advance of the engagement of the plunger surfaces with the O ring or other sealing member 39. This serves to protect the sealing member 39 and to increase the effective life thereof.

The plunger 45 serves to effectively seal the outlets 32, despite the clearance between said parts, by virtue of the circumferential seals effected'at the opposite ends of said plunger at the shear ring 29 and sealing member 39 on the one end and at the sealing ring 39 on the other end. This sealing arrangement permits the parts to be manufactured with greater tolerances than would be possible in a device employing metal-to-metal fits. It will be noted also that by virtue of the provision of the knife edge 49 upon the plunger which serves to bite into the ring 29, the sealing action is not limited to a mere abutment of these parts and hence is effective to seal the joint atthis point inthepresence of highiblastingspressures. The: provision. of: the; knife edge 49. serves the: additional. function. of anchoring the sealin ring against laterahdisplacement.

Onev of the important. advantages of the device the factthat. the head 25" may be. removed easily and; quickly by: virtue of" the fast lead of threads Consequently; when the. device is to; bereconditioned, the head 25: is removedfrom the body l0, thereby facilitating" access to the plungerif or. inspection; thereof and also permitting inspection of the sealing rings: Ml and: 39. and the wiping ring: 31. A fractured inner peripheral section of the shearring is. then removed. from. the plunger; the action. of removing: the head having released the: large. diameter portion of the shear .ringautomaticallyz. A newshear ring is then applied in. place and the device is: reassembled. These. operations can be accomplished rapidly as will; be apparent, so that. the time required to reconditionthe device is small and the reconditioning: operation does not require the use of special tools nor of intricate or difficult manipulations. These: factors are of importance because they enable the device to bev conditioned in situ in the mine rapidly and' und'erconditions adverse to the handlingof small or intricate parts.

The provision or only one working part, namely the plunger, in the: device reduces wear upon thed'ev ice and makes the device very simple. The use of an annular shear member, which must be sheared completely circumferentially to release the plunger, assures an instantaneous blast discharge so that the fullworking effect of the charge is obtained; Eflici'ency is further insured because of the fact that thedev-ice will not shoot until thepressure necessary to shear the ring-29 is reached. Another important feature of the device is thatthere is no danger, as has occurred in some blast devices of this type, that air or gas may be trapped in the bod'y-or-shell at high pressure due to breakage of internal parts, which condition would present a problem of' potential danger to operators. It will be noted that the device avoids the use of check valves and all other parts which might be subject to failure which would result in trapping of the pressure;

Another important advantage of the device is that the simplicity of the internal construction assures the greatest possible volume in the device per unit size for the storage of the charge and permits its size to be held at a minimum with respect to the desired amount of the charge.

Another advantage is the fact that the device eliminates all necessity for internal structures,

such as rods to connect a valve with a control part, inasmuch as the plunger serves at the same time the following functions: valving of the outlet, pressure response to produce movement, and the shearing action to open the valve.

While the device has been described herein primarily as an air blast device, it will be understood that other gases at high pressure may be used to charge it insteadof air; It will also be understood that changes in the construction may be made within the scope of the appended claims without departing from the spirit of the invention.

I claim:

1. An indestructible blasting device comprising a tubular body, means at one end of said body for introducing therein a gas under pressure, a rigid cap detachably secured to the other end of said body and having a lateral outlet, a tubular plunger adapted to span said outlet and slidable in said cap, an enlarged head on said plunger defining a shoulder and providing a larger; pressure responsive area at the end-off the plunger facing saidmeans than at itsv Opposite end, and a shear ring clamped between said cap andjbody and en.- circling said plunger and engageable by said shoulder.

2. An indestructible blasting device comprising a tubular body, means at one end of said body for introducing therein a gas under pressure, a rigid cap detachably secured to the other end of saidloody and having a lateral outlet, a tubular plunger adapted to span said outlet and slidable in said cap, said plunger havingan enlarged head defining a shoulder and providing a larger pressure responsive area at the end of the plunger facing said means than at its opposite end, and a shear ring clamped between said cap and body andv encircling said plunger and engageable by said shoulder, said shoulder terminating in a peripheral cutting edge acting against said sheer ring.

.larged head defining a shoulder and providing a larger pressure responsive area at the end of the plunger facing said means than at its opposite end, and a shearring clamped between. said cap and body and encircling said plunger and engageable by said-shoulder, said body having acircumferential shoulder limiting movement of said plunger toward said means.

4. An indestructible blasting device comprising a tubular body, means at one end of said body for introducing therein a gas under pressure, a rigid cap detachably secured to the other end of said body andhaving a lateral outlet, a tubular plunger having a sliding fit in said cap, an enlarged head on saidplunger defining a shoulder and pro.- viding a larger pressure responsive area at the end of the plunger facing said means than at its opposite end, a shear ring clamped between said cap and body and encircling said plunger and engageable by said shoulder, annular sealing means bet-ween the inner end of said plunger and said cap, and a wiping member carried by said cap between said outlet and said sealing means and encircling said plunger.

5. An indestructible blasting device comprising a tubular body, means at one end of said body for. introducing therein a gas under pressure, a rigid cap detachably secured to the other end of said body and having a lateral outlet, a tubular plunger forming an outlet closure and having a sliding fit in said cap, an enlarged head on said plunger defining a shoulder and providing a larger pressure responsive area at the end of the plunger facing said means than at its opposite end, a shear ring clamped between said cap and body and encircling said plunger and engageable by said shoulder, and a central internal projection at the end of said cap normally spaced from said plunger but having a snug sliding fit in the inner end of said plunger when said plunger is released for pressure responsive movement.

6. An indestructible blasting device comprising a tubular body, means at one end of said body for introducingv therein a gas under pressure, a rigid cap detachably secured to the other end of said body and having, a lateral outlet, av tubular plunger forming an outlet closure and, having a sliding fit in said cap, an enlarged head on said plunger approaches the end of said cap upon pressure responsive movement thereof.

7. A blasting device comprising a two-part separable chambered housing having a lateral outlet in one part intermediate the plane of separation of said parts and one end of said housing, means for introducing a gaseous charge under pressure at the opposite end of the housing, a shear member clamped between said parts and projecting into the housing chamber, and a pressure responsive sleeve slidable in said housing and having a severing portion normally engaging said shear member to position the sleeve to span said outlet.

8. A blasting device comprising a two-part separable chambered housing having a lateral outlet in one part intermediate the plane of separation of said parts and one end of said housing, means for introducing a gaseous charge under pressure at the opposite end of the housing, a shear ring clamped between said parts and projecting into said housing chamber, and a pressure responsive sleeve adapted to span said outlet and having a circumferential shoulder bearing against said ring and adapted to shear said ring when said housing is charged at a selected pressure.

9. A blasting device comprising a two-part separable chambered housing having a lateral outlet in one part intermediate the plane of separation of said parts and one end of said housing, means for introducing a gaseous charge under pressure at the opposite end of the housing, a shear ring clamped between said parts and projecting into said housing chamber, a pressure responsive sleeve adapted to span said outlet and having a circumferential shoulder bearing against said ring and adapted to shear said ring when said housing is charged at a selected pressure, said ring and shoulder forming a seal between said sleeve and housing at one end of said sleeve, and a seal carried by said housing and encircling the opposite end of said sleeve.

10. A blasting device comprising a two-part separable chambered housing having a lateral outlet in one part intermediate the plane of separation of said parts and one end of said housing, means for introducing a gaseous charge under pressure at the opposite end of the housing, a shear ring clamped between said parts and projecting into said housing chamber, a pressure responsive sleeve adapted to span said outlet and having a circumferential shoulder bearing against said ring and adapted to shear said ring when said housing is charged at a selected pressure, said ring and shoulder forming a seal between said sleeve and housing at one end of said sl eeve, the inner wall of said housing having a groove adjacent the opposite end of said sleeve and a soft yielding O ring seated in said groove and encircling said sleeve.

11. A blasting device comprising a two-part separable chambered housing having a lateral outlet in one part intermediate the plane of separation of said parts and one end of said housing, means for introducing a gaseous charge under pressure at the opposite end of the housing, a shear ring clamped between said parts and projecting into said housing chamber, a pressure responsive tube adapted to span said outlet and having a circumferential shoulder bearing against said rin and adapted to shear said ring when said housing is charged at a selected pressure, said ring and shoulder forming a seal between said tube and housing at one end of said tube, a seal carried by said housin and encircling the opposite end of said tube, and a wiping ring carried by said housing between said outlet and said seal and encircling said tube.

12. A blasting device comprising a two-part separable chambered housin having a. lateral outlet in one part intermediate the plane of separation of said parts and one end of said housing, means for introducing a gaseous charge under pressure at the opposite end of the housing, a shear ring clamped between said parts and projecting into said housin chamber, a pressure responsive tube adapted to span said outlet and having a circumferential shoulder bearing against said rin and adapted to shear said ring when said housing is charged at a selected pressure, and inwardly projecting means carriedby the end of said hOllSillg opposite said first means adapted to fit in said tube to define a substantially sealed annular compressed gas cushioning chamber in advance of said tube upon released pressure responsive opening movement of said tube.

13. A blasting device comprising a two-part separable chambered housing havin a lateral outlet in one part intermediate the plane of separation of said parts and one end of said housing, means for introducing a gaseous charge under pressure at the opposite end of the housing, a shear ring clamped between said parts and projecting into said housing chamber, a pressure responsive slidable sleeve adapted to span said outlet and having a circumferential shoulder bearing against said ring and adapted to shear said ring when said housing is charged at a selected ressure, said sleeve having a larger pressure responsive area at the end facing said means than at its opposite end and said flange having a perimetral cutting edge engaging said shear rmg.

14. An indestructible blasting device comprising a tubular body, means at one end of said body for introducing therein a gas under pressure, a rigid cap detachably secured to the other end of said body and having a lateral outlet, a tubular plunger having a sliding fit in said cap and an enlarged head definin a shoulder and providing a larger pressure responsive area at the end of the plunger facing said means than at its opposite end, a shear ring clamped between said cap and body and encircling said plunger and engageable by said shoulder, and annular sealing means between the inner end of said plunger and said cap.

FRANK H. ARMSTRONG.

REFERENCES CITED ,The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1 1,667,055 Sloan Apr. 24, 1928 2,083,736 Noble June 15, 1937 2,122,706 Armstrong July 5 1938 2,268,227 Rose Dec. 30, 1941 

